A private investigator hired by a client who did not believe the official report into Whitney Houston’s death claims a drug overdose wasn’t the cause of the superstar’s death. According to Paul Huebl, drug dealers killed the Grammy-winning singer.

­“I have evidence that points to Whitney being a victim of high powered drug dealers who sent thugs to collect a huge debt she owed for drugs,” Paul Huebl told the National Enquirer.

Huebl was quoted as saying that Houston’s killers have been allegedly caught on tape, referring to a pair of unknown men who showed up a number of times at the Beverly Hilton where Houston was staying.

According to media reports, the singer owed up to 1.5 million dollars to drug dealers who allegedly sent enforcers to collect the debt.

The day before her death the 48-year-old star reportedly received a cocaine delivery.

On the day she died, on the eve of the Grammy Awards, Houston was left alone in her hotel room at the Beverly Hilton Hotel for only 45 minutes.

According to Huebl, that’s when the killers were caught on surveillance video sneaking into her room.

The investigator also disagreed with the results of the coroner’s report that stated that Houston’s death was accidental.

“Whitney’s body shows classic defense wounds that would have occurred while she was battling for her life,” Huebl told the Enquirer.

The report confirmed that the singer had cocaine in her system when she drowned in her hotel room. Toxicology results also revealed that one of the world's best-selling artists had used marijuana. The autopsy findings confirmed that heart disease contributed to her death on February 11.

Although several bottles of prescription medications were found in Houston's hotel room, coroner's officials stated earlier this year that they were "not considered to be related to the actual cause of death."